1. Field of the Invention
This invention relates to a method of treating a permeable subterranean formation using water soluble organic cationic polymers containing two quaternary ammonium moieties in the polymer repeating units in order to stabilize in the formation migrating fines such as silica, iron minerals and alkaline earth metal carbonates in the presence or absence of clay minerals.
2. Description of the Prior Art
The recovery of fluids such as oil and/or gas has been troublesome in areas wherein the subterranean formation is composed of one or more layers or zones which contain migrating fines such as silica, iron minerals, and alkaline earth metal carbonates. These fines tend to move or migrate to the well bore during the recovery of formation fluids from the particular layers or zones and frequently the migrating fines block the passageways leading to the well bore. Plugging or materially impairing the flow of the formation fluids towards the well bore results in a loss of these fluids to the producer or so decreases the rate of hydrocarbon recovery from the well as to cause the well to be shut down because it is economically unattractive to produce therefrom. An additional adverse factor resulting from the movement of the fines towards the well bore is that they are often carried along with the formation fluids to the well bore and pass through the pipes, pumps, etc. being used to recover the formation fluids to the surface with resulting damage to the moving parts thereof as the fines are very abrasive.
Secondary and tertiary methods of recovering hydrocarbons from a subterranean formation are well known. In general, such a method involves introducing a fluid, such as water, steam, etc., into one or more injection wells which penetrate the formation and forcing the fluid toward a production well. Migrating fine particles during such an operation can cause a decrease of the rate in which the fluid can be injected into the formation and can decrease the permeability or porosity of the formation.
Consequently, in efforts to overcome these problems, various methods have been developed for treating a subterranean formation in order to stabilize portions of the formation. For instance, U.S. Pat. Nos. 4,366,071; 4,366,072; 4,366,073; 4,366,074; and 4,374,739 disclose the use of certain organic polycationic polymers to prevent or reduce the ill effects of swelling clays and/or migrating fines in earth formations.
U.S. Pat. No. 4,199,484 discloses an epoxy resin composition for forming a porous permeable consolidated particulate mass.
U.S. Pat. No. 4,074,536 discloses the use of certain organosilicon compounds to decrease the degradation of natural and artificial consolidated permeable masses which have exposed silica surfaces and which are subject to attack by an aqueous media.
U.S. Pat. No. 3,743,019 discloses a method of controlling loose sands in a formation by introducing into the formation an acid curable resin composition and thereafter introducing into the formation an overflush solution containing an acyl halide hardening agent.
U.S. Pat. No. 3,625,287 discloses the use of organosilicon compounds in sand consolidation resins used in consolidating loose sands.
Other typical methods of consolidating formations are disclosed in U.S. Pat. Nos. 4,070,867 and 4,042,032.
All of the above-cited patents are assigned to the assignee of the present invention and are hereby incorporated by reference.
A major cause of the breakdown of the consolidating structure of both natural and artificially consolidated permeable masses is the contact of an aqueous medium with the exposed surfaces of the migrating fines and/or the dislocation of consolidating material which binds the permeable masses together. Contact of the exposed surfaces with rapidly flowing oil or gas may also cause fines migration. Exposed surfaces of migrating fines result in even the most carefully placed artificial consolidation formulations and procedures for a number of reasons. For example, under certain subterranean conditions, the consolidation may merely deteriorate with time; the consolidation may deteriorate due to thermal expansion and contraction and result in cracks in the consolidating structure; or by merely chemical attack or reaction of portions of the consolidating structure with fluids in the permeable mass.
When consolidation resins are used to control migrating fines, there are certain limitations in the use of these resins. For instance, these resins cannot be used in conjunction with hydraulic fracturing, fracture acidizing and acid stimulation treatments. A well shut-in time frame of 1 to 48 hours depending on the resin and well conditions is required for an effective consolidation treatment.